Short answers, pulled from the story.
Navy Captain Francis S. Low proposed the concept to Admiral Ernest J. King on the 10th of January 1942, and Lieutenant Colonel James Doolittle was assigned to plan the raid. The attack received immediate approval after tests showed two B-25 bombers could launch from an aircraft carrier on the 3rd of February 1942.
The Doolittle Raid occurred on the 18th of April 1942 with sixteen modified B-25B Mitchell bombers launching from the aircraft carrier Hornet. All sixteen aircraft successfully took off between 08:20 and 09:19 to strike targets in Tokyo, Yokohama, and other Japanese cities.
Fifteen of the sixteen aircraft proceeded toward eastern China where they crash-landed or bailed out over Zhejiang province. One crew led by Edward J. York flew to the Soviet Union and landed at Vozdvizhenka beyond Vladivostok before being interned until mid-1943.
Three American crewmen were killed in action or captivity while eight others were captured and later executed or died in prison. The subsequent Japanese Zhejiang-Jiangxi campaign resulted in an estimated 250,000 Chinese civilian deaths according to Chinese estimates.
The United States House of Representatives passed H.R. 1209 on the 19th of May 2014 to award the Doolittle Raiders a Congressional Gold Medal. The official ceremony took place at the Capitol Building on the 15th of April 2015.